Drawing instrument.



No. 764,933- PAT-ENTED JULY 5, 1904.

W. S. BOWNESS 6L G. L. JONES.

DRAWING INSTRUMENT.

APPLIOATION I'ILED JAN. 19, 1904. N0 MODEL.

Witnesses. l Inventors.

WALTER SCOTT BOVNESS AND atented uly A5, 1904.

y PATENT OEEICE.

CLARENCE LEWIS JONES, OF MONCTON, CANADA.`

DRAWING INSTFILIIVIENT- SPECIFICATION forming part of Letters Patent No. 764,033, dated July 5, 1904,

Original application filed September 28, 1903, Serial No. 174,877. Divided and this application tiled 'anual-y 19, 1904. Serial I f No.y 189,722. (No model.)

To all whom; it may concern:

Be lit known thatw-e, VVALTE-R. SCOTT Bow- NEss and CLARENCE LEWIS JONES, subjects of the King of Great Britain, residing at Moncton, inthe county of Westmoreland, Province of New Brunswick, Canada, have invented certain new and useful Improvements in Drawing Instruments, of which the following is a specification.

Iol Our invention relates to improvements in drawing instruments; and the object of the invention is to devise a curve-tracer which shall facilitate the work of preparation of drawings in which the curves represent the arc of a circle of dimensions too great to be correctly made from the instruments. as at present provided; and it consists, essentially, of a frame having suitable bearings therein, a pair of wheels independently journaled to- 2o ward one end of said frame, and a guidingwheel journaled at the other end, as particularly described in the specification and drawings led under Serial No. 174,877 on September 28, 1903, and of which this case is a di- 2 5 vision, and a stationary finger or pointer centrally located above the frame, and a wormand-gear mechanism controlling the line of direction of the guiding-wheel, the various parts being constructed in detail, as hereinafter more particularly described. 1

Figure 1 is a plan view of the instrument from above. Fig. 2 is a longitudinal sectional view of the instrument. Fig. 3 is a plan view of the instrument from below.

3 5 Like characters of reference indicate corresponding parts in each ligure.

a is the frame, having the bearings b and c and the wheels d and e journaled independently therein, as explained in detail in our Jformer application.

j' is a'rod journaled in suitable bearings g in the top of the frame a, having a thumbwheel it at its outer end and a worm c' intermediate of its length and midway between the bearings.

j is an indicating-nger suitably secured and stationary on the frame a, pointing inwardly and centrally located over the worm e'.

' la is a segmental gear divided into degrees f or suitable measurements and meshing with f the worm e'.

1 indicates radial arms extending from the segmental gear lc and merging into the annu` lar end m., concentric with the segmental gear. The annular end m has al reduced lower portion n, which turns in a correspondingly-made portion 0 of the frame a.

2 indicates slots formed in the portion 0, designed to allow the passage of lugs 3, formed onthe annular endm when the same is introduced into the portion 0, and on the turning into place of the said annular end in the fore part of theframe the lugs pass under a part of the -portion 0 and hold the parts together.

p is a rod suitably journaled in the reduced lower portion n and carrying the wheel q.

r represents rods secured to the journals of the rod p. The pencil is suitably secured to oneof these rods, as shown in the drawings. 7o

In the operation of this instrument the thumb-wheel of the worm rod or shaft controls the position of the segmental gear, and consequently the line of direction of the guiding-wheel, the angle of the bearings of the said guiding-wheel in relation to the frame c being affected at each revolution or portion of revolution ot' the said thumb-wheel. The segmental gear is mathematically divided into degrees or suitable measurements and these 8O measurements or degrees marked thereon. The iXed linger j points directly over the markings on the gear, so that any turn of the thumb-wheel will move the gear past the iinger one way or the other and leave it point- 8 5 ing over the particular degree desired for the describing of the curve. The arms 1, forming part o1l the segmental gear, and the any nular end being concentric with the saidsegmental gear and having the bearings of the 9o Wheel q xedly attached thereto, the said wheel must always follow circumferentially with the segmental gear. The pencil is attached to one or other of the rods, and consequently must follow the direction taken by the guiding-wheel q, and allowance must be made in setting the instrument for the larger or smaller circle described than would be the case if the mark was made directly by the wheel. y Y

The use of the instrument is extremely simple, for after setting the carriage is simply moved along the paper, starting the pencil at the point where the curve is designed to emanate and finishing at the proper point of termination.

What we claim as our invention is- 1. In a drawing instrument, the combination with a frame having a plurality of bearings arranged therein, of a guiding-wheel journaled at one end thereof, a pair of wheels independently journaled one of the other toward the other end of said frame, a segmen-v tal gear, a radial arm extending therefrom, means attached to said arm for turning said guiding-wheel, a fixed finger centrally arranged on the frame and extending over the segmental gear, a rod having a worm intermediate of its length meshing with said gear, and journaled in suitable bearings in the upper side oil the frame, and provided with a suitable thumb-wheel, as and for the purpose specified.

2. In a drawing instrument, a frame having a plurality of bearings arranged therein, and a pair of wheels independently journaled toward one end of the frame, in combination with a guiding-wheel located at the other end of the frame, an arc-shaped dial having radial arms extending therefrom terminating in an annulus concentric with said dial, said-annulus turning in the frame, and having bearings in which the guiding-wheel is journaled, a stationary linger from the frame pointing to said dial, and means for altering the position of the dial in relation to the nger, as and for the purpose specified.

3. In a drawing instrument, a frame having a plurality of bearings arranged therein, and a pair of Wheels independently journaled toward one end of the frame, in combination with a guiding-wheel located at the other end of the frame, an arc-shaped dial having a toothed edge and radial arms extending therefrom terminating in an annulus concentric with said dial, said ann ulus turning in the frame and having bea-rings in which the guiding-Wheel is journaled, a stationary finger from the frame pointing to said dial, and a rod journaled in projections from the frame and having a worm intermediate of its length meshing with said toothed edge, and a thumb- Wheel secured on its outer end, as and for the purpose specified.

Signed at Moncton, in the county of Westmoreland, in the Province of New Brunswick, Canada, this 12th day of January, 1904.

WALTER SCOTT BOWNESS. CLARENCE LEWIS JONES. Witnesses:

MINNIE R. SEFTON, E. ATTEL REILY. 

